import java.util.Random;

public class test31 {
    //开发验证码 前四位大小写字母随机,第五位为随机数字
    public static void main(String[] args) {
        char[] a = new char[52];
        for (int i = 0; i < a.length; i++) {
            if (i <= 25) {
                a[i] = (char) ('a' + i);
            } else {
                a[i] = (char) ('A' + i-26);
            }
        }
        String s = "";
        Random r = new Random();
        for (int i = 0; i < 4; i++) {
            int b=r.nextInt(a.length);
            s = s + a[b];
        }
       int number = r.nextInt(10);
        s=s+number;
        System.out.println(s);
    }
}